This invention relates to low cost valve devices, and more particularly to manually operated valve systems for controlling irrigation and aspiration flows to surgical sites.
In surgical applications, most notably in laparoscopic and endoscopic procedures, it is preferred to utilize disposable elements for at least certain ones of the surgical instruments, rather than subjecting patients to the potential dangers of cross-contamination from prior users due to inadequate sterilization. This conclusion applies not only to simple surgical instruments, but to more complex instruments which may be used to provide dynamic functions during the duration of a surgery. For example, it is often desired to irrigate an operative site with a sterile solution and then to withdraw or aspirate fluid under suction. The aspirated fluid may include not only an irrigation solution, but also blood and other fluids, tissue and fragments. A number of procedures use an elongated probe and control flows into and out of the operative site by an externally operated valve device that is conveniently manipulated by the surgeon. This type of valve device has been used for many years, but earlier units were primarily expensive, complex designs that were intended to be reusable. Further, since the probes were fixed to the valve structure, the surgeon was afforded little opportunity to use the instrument in a variety of operating modes, or manipulate it readily in different positions.
More recently, workers in the field have devised disposable manual valve systems for use in surgical applications, these usually being called "trumpet valves" because key members on the top of two adjacent and parallel valve barrels can be selectively depressed by the surgeon against compression springs. An example of such a type of system is U.S. Pat. No. 5,064,168 to Raines et al. (assigned to Burron Medical, Inc.) in which an offset base portion of the valve is configured together with a valve barrel and an interior movable member for flow control. However, this design has interior corners and has not been found suitable for a number of modern laparoscopic and endoscopic procedures, in which it is critical to avoid restrictions and distortions in the flow path. If the aspirated flow does encounter restrictions, tissue or particulate might clog the instrument, a consequence which is to be avoided if at all possible.
The patent to Dorsey, U.S. Pat. No. 5,188,591 describes a trumpet valve which is intended to have certain operating advantages for irrigation control, based upon a bilaterally symmetrical arrangement of two valve chambers with respect to a transverse common conduit at one side, with ports extending radially outwardly from the other side in an orthogonal direction. The common conduit is in communication with each of the valve chambers through side orifices, so that a probe can be attached to either end of the common conduit. Because the irrigation and aspiration conduits couple into the opposite side of the chambers from the common conduit, this arrangement can be used by a right-handed surgeon with the probe extending from one end of the common conduit, or by a left-handed surgeon if the probe is reversed to the opposite end of the common conduit. However, the internal flow paths are restricted in size, because of the necessity of coupling into and out of side conduits, and because the geometry requires a number of O-ring seals and the use of biasing springs in the bottom of the chamber.